Liquid dispensing devices have been on the market for ages. In particular, pressure driven dispensing devices rely on a pressurized gas raising the pressure to a level of about 0.1 to 15 bar, usually of 0.5 to 1.5 bar above atmospheric in the interior of a container containing the liquid to be dispensed, such as a beverage like beer or other carbonized beverages. Since the liquid contained in the container is at a higher pressure than atmospheric, it will flow out of the container through a dispensing tube upon fluidly connecting it with ambient. For dispensing a liquid, the interior of the container must therefore first be fluidly connected to, on the one hand, a source of pressurized gas to raise the pressure in the container and, on the other hand, to the ambient through a dispensing tube comprising a valve for dispensing the liquid. These connections usually run through a specially designed closure of the container. For aesthetic reasons and to ease the connections required for the use of such dispensing containers, the latter are usually mounted into a dispensing appliance which allows the various fluid connections to be put in place rapidly and easily. In optimal appliances, this operation is completed by simply clicking into place the top chime (or hood) of the appliance onto the container's closure.
The gas is either fed directly into the container containing the liquid like e.g., in U.S. Pat. No. 5,199,609 or between an external, rather stiff container and an inner, flexible vessel (e.g., a bag or a flexible bottle) containing the liquid to be dispensed, like in U.S. Pat. No. 5,240,144 (cf. appended FIG. 1(a)&(b)); the latter system is called “dispensing bag-in-container.” Both applications have their pros and cons which are well known to the persons skilled in the art. The present invention applies to both types of delivery systems, but is particularly advantageous for dispensing bag-in-containers-or simply “bag-in-container”—which meaning is herein restricted to dispensing containers wherein the dispensing of the liquid is driven by a pressure difference across the inner bag wall, preferably by injection of a pressurized gas into the space between inner bag and outer container.
The compressed gas may be provided by a compressor, included in a specific appliance (cf. U.S. Pat. No. 5,251,787), or contained in a compressed gas bottle (cf. U.S. Pat. No. 5,383,576, FIG. 7). Alternatively, the container may be pre-pressurized, with enough pressure to dispense part or the whole content of the container (cf. WO2010/031764). This solution is advantageous as it does not require the connection of the container to an external source of pressurized gas. It has, however, the drawback that the outer container must be sufficiently robust to resist deformation under the relatively high pressure required for the dispensing. It is possible to limit or even eliminate the level of pre-pressurisation of the container, by storing a sufficient amount of gas either in a small cartridge or adsorbed on a carrier, which are placed in the container and designed to release gas when required as disclosed in WO2008060152.
More recently, a market for home appliances of smaller size of the order of 0.25 to 12 liters, typically of 2 to 5 liters has been developing rapidly. For technical and economic reasons, it is sometimes preferable to use no compressor or large compressed gas bottle and the propellant gas can then be stored in a rather small pressurized cartridge closed by a cap or a membrane. The cap or membrane of these home dispensers may be pierced open in plant but, to avoid risks of leakage, it is usually preferred that the piercing of the closure be performed by the end-user prior to using the device for the first time. Examples of such devices can be found in EP149352, WO2007/145641, GB1427732, GB1163761, U.S. Pat. No. 3,372,838, and WO2006/128653, and are illustrated in attached FIG. 1.
The propellant gas stored in a bottle or cartridge is at a pressure much higher than the 0.5 to 1.5 bar above atmospheric required in the container to drive the dispensing of the beverage. It is therefore necessary to interpose between the gas bottle or cartridge and the container a pressure regulating valve for reducing the pressure of a propellant gas stored in a bottle or cartridge at a first, high pressure to a second, lower pressure suitable for driving the dispensing of the beverage. Upon use, the gas is fluidly connected to the container at a controlled pressure through a duct running through the closure and opening either in the space containing the liquid (cf. FIG. 1(a)) or in the space between the inner bag and outer container of a bag-in-container (cf. FIG. 1(b)). The solutions discussed above of storing the pressurizing gas in the container either in a small cartridge or adsorbed on a carrier are particularly suitable for smaller home appliances, but to date they are not quite so widespread yet. When implemented, however, no external connection is required and the closure needs not comprise an opening for receiving a pressurized gas tube.
The liquid contained in the container can be dispensed by pressure driving its flow in a dispensing tube fluidly connecting the interior of the container with the ambient. Like the gas duct fluidly connecting the source of pressurized gas with the container, the dispensing tube usually runs through an aperture in the closure of the container and opens in the volume containing the liquid, regardless of whether a bag-in-container or a “traditional” pressure driven container is used. Since the pressure in the container is usually constantly maintained above atmospheric the dispensing tube normally comprises a valve in order to control the dispensing of liquid. In case the pressurized gas is injected in contact with the liquid to be dispensed (cf. FIG. 1(a)) the dispensing tube must extend deep down into the container, since the liquid at a level below the opening of the dispensing tube may not be dispensed if the container is maintained in its upright position (as is usually the case). This is not mandatory in case of bag-in-containers (cf. FIG. 1(b)), since the collapse of the inner bag ensures that at all time the liquid is in contact with the closure. In some cases, however, it is desirable to have the dispensing tube penetrate into the bag to better control the collapse of the bag. But this solution has the disadvantage of having to introduce a long stem deep into the container, which operation may be cumbersome, and it is usually preferred—if possible—to control the collapse of the inner bag by other means.
WO2009090223, WO2009090224, and WO2009090225 disclose closures for pressure driven dispensing containers comprising a first aperture for receiving a dispensing tube and a second aperture for receiving the gas duct by simply click fitting the container into a dispensing appliance. The closures disclosed in said applications are particularly suitable for bag-in-containers WO2009090223 discloses a closure having a base comprising a pierceable part, the pierceable part being defined by a sidewall extending transversally with respect to the base and a bottom thereby creating a indent therein, said sidewall and/or bottom comprising several lines of weakened material strength, characterized in that said lines divide the sidewall and/or bottom in several wedge, but they can be used for normal pressurized containers by simply positioning the aperture for the gas duct to open into the space containing the liquid. In particular, formed parts. Said opening is pierced open upon introduction of the dispensing tube therethrough when the container is click fitted into a dispensing appliance. The problem with the closure described therein is that if the container is retrieved from the appliance before it is empty, e.g., for mounting a new container with a different beverage or for cleaning the appliance, the liquid remaining in the container cannot be protected from contact with the ambient during storage, as the dispensing aperture of the container's closure is irreversibly open. This may result in the degradation of the liquid still present in the container, in particular if it is a carbonated beverage such as a beer or a soda. Furthermore, spillage of any liquid remaining in the container in case it is tilted cannot be prevented with the present closures.
There are several resilient closures for liquid containers described in the art, which open upon dispensing and close back when not in use. Generally, these closures comprise a portion made of a resilient material with one or several slits which are naturally closed. The slits open upon application of a pressure inside the container, for example by turning the container up side down, or by pressing the flexible walls of a container, and resiliently close back when the pressure is reduced. The slitted resilient portion often has a concave shape to accentuate the spring back effect. Examples of such closures are described in EP1858770, U.S. Pat. Nos. 6,769,577, 6,045,004, EP1763475, US2007138189, EP1730044. These closures, however, are not suitable to operate at the pressures used in pressure dispensing containers, and in particular in case of carbonated beverages, the liquid is to be stored in the half empty container under pressure, which would unevitably open such closures.
The present invention concerns closures for “pressure driven dispensing containers,” which term refers here to containers which dispensing of the liquid contained therein is driven by a pressurized gas raising the pressure inside the container above atmospheric. Dispensing of the liquid out of a pressure driven dispensing container therefore does not require the tilting of the container to bring the mouth thereof at a level lower than the level of the liquid, nor the squeezing of the external walls of the container, e.g., by hand. The pressurized gas may be stored within the container prior to use or be introduced into the container from an external source.
Valves for pressure driven dispensing containers are disclosed e.g., in WO00/03944 and EP1683755. But these valve designs are rather complex with moving parts, their production requiring cost and time extensive assembly steps, not compatible with rather disposable containers to be mounted on home appliances of rather modest size. For such applications, characterized by a rather unfavourable cost ratio between the liquid (beverage) and the container compared with systems of larger size, it is preferable to reduce the cost of the valve and therefore to develop a design comprising no moving part and, possibly requiring no assembly step.
There are closures on the market which may be pierced opened by a dispensing duct and resiliently and sealingly closing back upon withdrawal of the duct. For instance, vials closed with a rubber or foam closure may be pierced open by introducing a syringe needle and sealingly and resiliently closes back as the needle is retrieved. But the dispensing tube diameter required to ensure an acceptable flow rate of the order of 0.5 to 2.5 l/min, or even up to 5 l/min, typical of beverage dispensing containers does not allow to upscale the vial solution to pressure driven dispensing liquid containers.
WO2009/050713 discloses a one way valve for inflatable articles, wherein a lid in the valve is pushed open by the introduction of the tube of an inflating pump, said lid being mounted on resilient means such as to spring back into its closed position as the pump tube is withdrawn. This solution is not suitable for the closure of pressure driven dispensing container because (a) it comprises multiple components to be assembled which is not compatible with the cost requirement of a beverage dispensing system, and (b) the pushed open lid remains in contact with the opening of the pump tube, which is no problem when the fluid flow pushes the lid away from the tube as is the case with a pump, but is unsuitable when the liquid flow pushes the lid back against the tube as is the case with a dispensing container, thus partially obturating the dispensing pipe inlet and disrupting the liquid flow out of the container.
U.S. Pat. No. 2,568,976 discloses a flexible valve for inflatable articles wherein a flexible membrane is resiliently pressed by a spring against a section of the inflatable article wall comprising an opening. This valve is designed for use with inflatable products having no rigid wall and is not suitable for use with closures for dispensing containers.
WO2009/020425 discloses a non return valve to be fastened together inside a container for air or liquids such as mattresses, cushions, etc. The non-return valve is formed of two sheets made of a non-rigid plastic or rubber material, welded together to form an through channel. The valve further comprises a resilient device spanning the through channel, said resilient device being fixed on two opposite sides of said through channel, and being biased such as to stretch the sheets and thus close tight the through channel. Here again, the valve disclosed therein is not suitable for the closure of a dispensing container because rather large in dimensions, and requiring welding and assembly of multiple components, which is not consistent with the economics of beverage dispensing containers.
There therefore remains a need for a closure of a pressure driven liquid dispensing container allowing the easy and swift mounting thereof into a dispensing appliance. The closure should allow the automatic and fluid tight sealing of the dispensing aperture upon retrieval of the container from the appliance. The present invention proposes such closure which may be produced rapidly and economically, preferably without any assembly step.